Distillation apparatus

ABSTRACT

A modular distillation apparatus including at least one heat exchanger that preheats contaminated liquids; a heater that heats the contaminated liquid from the heat exchanger; an evaporator condenser adapted to boil the contaminated liquid coming out of the heater to produce water vapor and contaminant concentrate, and condense the water vapor into distilled water; a vacuum chamber capable of operating at below atmospheric pressure, the vacuum chamber housing the evaporator condenser and including at least one partition to separate the distilled water from the contaminant concentrate; a vapor compressor operably associated with the vacuum chamber to receive water vapor from the evaporator condenser in the vacuum chamber and pump the water vapor at pressure back through the evaporator condenser, wherein the heat exchanger recovers sensible heat from outgoing condensed distilled water and contaminant concentrate recycled from the vacuum chamber.

STATEMENT OF CORRESPONDING APPLICATIONS

This application is based on the Provisional specification filed in relation to U.S. Patent Application No. 60/913,731, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a distillation apparatus. In particular the present invention relates to a distillation apparatus capable of producing distilled water from contaminated liquids using heat distillation under a vacuum and including recycling of latent and sensible heat within the apparatus to improve energy efficiency.

BACKGROUND ART

Traditionally liquid distillation systems, such as those used in desalination, ground water remediation or liquid recycling plants, have high energy requirements which can account for between 50% and 70% of the total operating costs of such a plant. These high operating costs can make such plants prohibitively expensive and impractical, particularly for applications in developing countries and in locations without a reliable energy supply.

In addition, known methods of liquid treatment such as reverse osmosis, utilising activated carbon filtration and optionally ultra-violet or ozone exposure, typically do not have the capacity for efficient treatment of heavily contaminated liquids such as sea water or brackish water and usually require pre-treatment such as pre-filtration and/or chemical treatment. Such known treatment methods produce waters which have total dissolved solid (TDS) concentrations of 500 to 1000 ppm which can result in treated water with odour and/or unpleasant aftertaste and is too saline to use for agricultural irrigation. Additionally, filtration can lead to operational problems such as filter clogging and the need for sterilisation of the filtration apparatus on a regular basis to prevent build-up of mould, algae and bacteria contaminants.

A further disadvantage with known liquid treatment systems is the lack of portability to a site and scalability on site in situations where increased capacity is required quickly such as in emergency relief situations.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION

According to one aspect of the present invention there is provided a distillation apparatus to produce distilled water from a contaminated liquid including:

-   -   at least one heat exchanger that preheats the contaminated         liquid;     -   a heater that heats the contaminated liquid from the heat         exchanger;     -   a degasser to remove non-condensable gases from the heated         contaminated liquid from the heater;     -   an evaporator condenser adapted to         -   boil the contaminated liquid from the heater to produce             water vapor and contaminant concentrate, and         -   condense the water vapor into distilled water;     -   a vacuum chamber capable of operating at below atmospheric         pressure, the vacuum chamber housing the evaporator condenser         and including at least one partition to separate the distilled         water from the contaminant concentrate;     -   a vapor compressor operably associated with the vacuum chamber         to receive water vapor from the evaporator condenser in the         vacuum chamber and pump the water vapor at pressure back through         the evaporator condenser

wherein

-   -   the at least one heat exchanger recovers sensible heat from         outgoing condensed distilled water and contaminant concentrate         recycled from the vacuum chamber;     -   the evaporator condenser transfers the latent heat from the         condensing water vapor to boil the contaminated liquid, and     -   the distillation apparatus operates as an standalone unit.

Preferably, the distillation apparatus includes a vacuum pump operably associated with the vacuum chamber.

Preferably, the evaporator condenser boils the contaminated liquid in the temperature range 40° C. to 100° C.

Preferably, the evaporator condenser includes a plurality of non-porous plates, each of the plates having a surface which on contact boils the contaminated liquid to produce water vapor and a surface which on contact condenses the water vapor into distilled water.

Preferably, the plurality of non-porous plates has a hydrophilic outer surface.

Preferably, the hydrophilic plates have a thickness of between 0.1 mm to 0.25 mm.

Preferably, the vacuum chamber further includes at least one baffle to accelerate vapor velocity to separate droplets of boiling liquid residues from the vapor.

Preferably, the vacuum chamber includes at least one transparent and removable panel.

Preferably, the evaporator condenser is a rising film or a falling film type heat exchanger.

Preferably, the evaporator condenser operates in a vacuum inside the vacuum chamber.

Preferably, the vacuum chamber further includes a means to circulate the water vapor to accelerate vapor condensation.

Preferably, the distillation apparatus further includes a contaminated liquid pump to pump contaminated liquid into the at least one heat exchanger.

Preferably, the distillation apparatus further includes a distillate pump to pump the distilled water from the vacuum chamber through the at least one heat exchanger.

Preferably, the distillation apparatus further includes a concentrated contaminated liquid pump to pump the concentrated contaminated liquid through the at least one heat exchanger.

Preferably, the distillation apparatus may be housed and transported within ISO shipping containers with like distillation apparatus.

Preferably, the distillation apparatus may operate for a continuous period without interruption.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a schematic view of the process followed by the distillation apparatus of the present invention;

FIG. 2 shows a schematic sectional view of the distillation apparatus of the present invention; and

FIG. 3 shows perspective views A and B of the distillation apparatus of FIG. 2;

FIG. 4 shows schematic perspective views A and B of the distillation apparatus of FIG. 2;

FIG. 5 shows a schematic perspective view of four apparatus of the present invention in an ISO shipping container.

BEST MODES FOR CARRYING OUT THE INVENTION

FIG. 1 shows a schematic view of the distillation apparatus generally indicated by arrow 1. Contaminated liquid 100 is pumped by feed pump 2 and preheated on passing through a heat exchanger 3, which recovers heat from the two output liquid streams: pure distilled water 200 pumped from distillate pump 4 and concentrated residues 300 pumped at contaminant pump 5. Heated to within a few degrees of boiling temperature, the liquid 100 next passes through a start-up heater 6, then enters vacuum chamber 7 containing evaporator/condenser unit 8 comprising a plurality of dynamic film thermal plates (not shown). A vacuum pump 9 attached to a vacuum chamber 7 produces a vacuum to be attached inside the chamber 7. The liquid 100 boils as it passes through the evaporator condenser unit 8, and the water vapor is drawn off at 10 by a vapor compressor 11. The remaining concentrated contaminant liquid 300 flows out of the chamber 7 at point 12, carrying away all contaminants.

The pure water vapor 400 extracted by the vapor compressor 11, is pressurized—raising its temperature 400A and injected into the condenser at 13, where its latent heat is released through the plates as it condenses into pure distilled water, thereby causing the contaminated liquid 100 to boil. Because most of the process heat is recovered and recycled within the heat exchanger 3 and the evaporator/condenser unit 8, overall specific energy requirements are significantly reduced in comparison with conventional distillation systems. Following the start-up period, there is little or no energy required to directly heat the water. The only energy input needed to operate the system is used by the vapor compressor 11, four pumps 2, 4, 5, 9 and the controls (not shown). Purity of the output distilled water product is less than 10 ppm of total dissolved solids (TDS).

FIG. 2 shows a schematic sectional view of the distillation apparatus 1. The vacuum chamber 7 housing the evaporation condenser units 8 is connected to the vapour compressor unit 11 contained in a vapour compressor housing 11A.

The evaporator condenser plates each have a boiling surface facilitating evaporation of the feed contaminated liquid 100 into water vapour 400 and a condensing surface facilitating condensing the water vapour 400A into distilled water 200. The latent heat released on condensing of the water vapour 400A into distilled water 200 is conducted through the plates which facilitate the boiling and evaporation of the feed contaminated liquid 100 into water vapour 400. The plates are bonded or welded to prevent contamination of feed contaminated liquid 100 and distilled water 200.

The plates may be made from food containment metals such as titanium, stainless steel or aluminum. The plates have a surface morphology to produce a hydrophilic effect which enhances the latent heat transfer of the plates and preferably have a thickness of between 0.1 mm to 0.25 mm. The evaporator condenser 8 may be a rising film or falling film evaporator type and may operate under vacuum pressure or at atmospheric pressure.

The heated liquid feed 100 enters the vacuum chamber 7 under pressure and boils on contact with the boiling surface of the evaporator condenser plate. The resulting water vapour 400 is extracted by the vapour compressor 11 and injected under pressure (400A) back into the chamber 7 via a compressed water vapour duct 14. The latent heat of the compressed water vapour 400A is released through the evaporator condenser plates as the water vapour 400A condenses into pure distilled water 200 thereby causing the contaminated liquid 100 to boil. The boiling point of the contaminated liquid under vacuum in the vacuum chamber is preferably between 40° C. and 100° C. The two outputs of the distillation apparatus 1 are the waste concentrate 300 and distilled water 200 which exit from the apparatus 1.

FIGS. 3 and 4 show perspective sectional front views 3A, 4A and back views 3B, 4B of the distillation apparatus 1. The vacuum chamber 7 of the distillation apparatus 1 has a transparent and removable front panel (not shown) through which the evaporation condensing processes can be viewed and allowing service access to the evaporation condenser units 8 for maintenance. The removable panel is sealed with “P” or “D” shaped silicone seals to ensure vacuum integrity of the panel. The distillation apparatus 1 is optionally contained in an enclosure 15 including forklift base 16 for convenient portability. The vapour compressor 11 has an associated compressor drive motor 11A and belt drive contained in a housing 11B. Hatches 17 and 17A provide internal access to the chamber 7 for service and maintenance. Pumps 18A-C pump distilled water, feed contaminant liquid and waste concentrate to the heat exchanger 3. A degasser 19 separates non-condensable gasses from the heated contaminant liquid 100, such as oxygen from the air, in the inlet to the vacuum chamber 7 from the heat exchanger. Removal the build-up of such non-condensable gasses in the vacuum chamber 7 prevents coating of the evaporator condenser 8 and reduction of the efficiency of same.

Control of the distillation apparatus 1 operation cycle is fully automatic, via a control panel 20, from initial warm-up through distillation and shut down as well as a self-cleaning procedure. At intervals determined by the quality of the liquid 100, the distillation apparatus 1 ends the distillation cycle and starts the self-cleaning procedure which lasts approximately 100 minutes. Automatic fail-safe valve arrangements ensure that waste water distillate 300 containing contaminant impurities cannot be mixed with the distilled water output product 200.

Service 21 and power access 22 provide further maintenance points to the base of the apparatus 1.

The vapour compressor 11 is separated from the vacuum chamber 7 by a separator 23. The vacuum chamber 7 includes at least one baffle 24 to accelerate vapor condensation inside the vacuum chamber 7. The vacuum chamber 7 also includes a vapour recycle means 25, such as a fan to re-circulate a portion of the water vapour inside the vacuum chamber 7, to accelerate water vapour condensation on the plates of the evaporator condenser 8.

The evaporator condenser 8 maintains a higher pressure on the condensing side of the plates to ensure that, in the event of leakage occurring within or around the evaporator condenser, leakage will be from the distilled water into the contaminated liquid thus ensuring the quality of the distilled water output product is not compromised. The performance and status of the distillation apparatus 1 can be monitored from a remote location to minimise maintenance inspections and onsite personnel surveillance time.

FIG. 5 shows a schematic perspective view of two sets of four modules of the distillation apparatus 1 transported inside an ISO 20 foot shipping container 26 modified with a hydraulically operated roof 27 and wall 28 to provide service access to the distillation apparatus 1. Easy transportation of the distillation apparatus 1 enables efficient upscale production of distilled water at a particular site.

Applications of the distillation apparatus 1 include those situations where a secure drinking water supply is needed such as in emergency relief conditions or in manufacturing industry which require ultrahigh purity distilled water such as water bottling, dairy, finishing, glycol recovery, ground water remediation, desalination and waste water recycling and concentration industries, the food and beverage industry, microelectronics and pharmaceutical industries as well as toxic and hazardous waste recovery water treatment as well as providing emergency relief pure drinking water from water that has been contaminated naturally or by man.

Thus, preferred embodiments of the present invention may have a number of advantages over the prior art which may include:

-   -   high purity distilled water production;     -   environmentally friendly high purity distilled water production;     -   fail-safe operation, irrespective of contaminant liquid quality;     -   ability to process high solids liquids with minimal         pre-treatment;     -   vacuum induced low boiling temperature minimises scale build-up         and maintenance;     -   easy to operate fully automated control system with remote         monitoring and diagnostics;     -   able to operate continuously for an uninterrupted extended         period;     -   built-in self-cleaning and sterilization with minimum on-site         maintenance;     -   compact design with small physical footprint enables easy         portability and scalability;     -   modular construction enables easy maintenance;     -   improved energy efficiency resulting in lower operating cost,         and     -   readily portable to different locations.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims. 

1. A distillation apparatus to produce distillate from a contaminated liquid including: at least one heat exchanger that preheats incoming contaminated feed liquid by recovering and recycling sensible heat to the incoming contaminated feed liquid from outgoing condensed distilled water and contaminant concentrate pumped from the vacuum chamber; a start-up heater that heats the contaminated feed liquid from the heat exchanger; a degasser to remove non-condensable gases from the heated contaminated feed liquid from the heater; a mechanical vapor recompression (MVR) evaporator condenser including: a plurality of non-porous plates, each of the plate having a first surface which on contact boils the contaminated feed liquid from the heater to produce water vapor and contaminant concentrate and a second surface which on contact condenses the water vapor into distilled water; a single vacuum chamber capable of operating under vacuum or low positive pressure, the vacuum chamber housing the MVR evaporator condenser and including at least one partition to separate the distilled water from the contaminated feed liquid; and a vapor compressor operably associated with the vacuum chamber positioned on a horizontal or vertical axis to receive water vapor from the MVR evaporator condenser in the vacuum chamber and pump the water vapor at pressure back through the MVR evaporator condenser wherein the MVR evaporator condenser transfers the latent heat of evaporation from the condensing water vapor from the second surface of each of the plurality of non-porous plates to boil the contaminated feed liquid on the first surface of the plurality of non-porous plates; the distillation apparatus operates as an standalone unit; and the non-porous plates of the MVR evaporator condenser have a thickness of between 0.1 mm to 0.25 mm.
 2. The distillation apparatus as claimed in claim 1, wherein the distillation apparatus includes a vacuum pump operably associated with the vacuum chamber.
 3. The distillation apparatus as claimed in any one of claim 1 or 2, wherein the MVR evaporator condenser boils the contaminated liquid in the temperature range 40° C. to 110° C.
 4. The distillation apparatus as claimed in any one of claims 1 to 3, wherein the non-porous plates have a hydrophilic outer surface.
 5. The distillation apparatus as claimed in any one of claims 1 to 4, wherein the vacuum chamber further includes at least one baffle to accelerate vapor velocity to separate droplets of boiling liquid residues from the vapor.
 6. The distillation apparatus as claimed in any one of claims 1 to 5, wherein the vacuum chamber includes at least one transparent and removable panel.
 7. The distillation apparatus as claimed in any one of claims 1 to 6, wherein the MVR evaporator condenser is a rising film or a falling film type heat exchanger.
 8. The distillation apparatus as claimed in any one of claims 1 to 7, wherein the MVR evaporator condenser operates in a vacuum inside the single vacuum chamber.
 9. The distillation apparatus as claimed in any one of claims 1 to 8, wherein the boiling action of the contaminated feed liquid between and over the plurality of non-porous plates circulates the contaminated feed liquid in the MVR evaporator condenser and enhances transfer of the latent heat of evaporation from the second surface to the first surface of the plurality of non-porous plates.
 10. The distillation apparatus as claimed in any one of claims 1 to 9, wherein the single vacuum chamber further includes a means to circulate the water vapor to enhance vapor condensation.
 11. The distillation apparatus as claimed in any one of claims 1 to 10, wherein the distillation apparatus further includes a contaminated feed liquid pump to pump contaminated feed liquid into and through the at least one heat exchanger and into the vacuum chamber.
 12. The distillation apparatus as claimed in any one of claims 1 to 11, wherein the distillation apparatus further includes a distillate pump to pump the distilled water from the vacuum chamber through the at least one heat exchanger.
 13. The distillation apparatus as claimed in any one of claims 1 to 12, wherein the distillation apparatus further includes a concentrated contaminated liquid pump to pump the concentrated contaminated liquid from the vacuum chamber through the at least one heat exchanger.
 14. The distillation apparatus as claimed in any one of claims 1 to 13, wherein the distillation apparatus has purpose built interconnecting pipe work and clamp valves.
 15. The distillation apparatus as claimed in any one of claims 1 to 14, wherein the distillation apparatus has inbuilt clean in place capability.
 16. The distillation apparatus as claimed in any one of claims 1 to 15, wherein a higher pressure on the second side of the plurality of non-porous plates in the MVR evaporator condenser than the first side of same ensures fail safe distillation.
 17. The distillation apparatus as claimed in any one of claims 1 to 16, wherein the distillation apparatus operates for a continuous period without interruption.
 18. The distillation apparatus as claimed in any one of claims 1 to 17, wherein the distillation apparatus is housed and transported within ISO shipping containers with like distillation apparatus. 